1. Field of the Invention
The present invention relates to a housing for a magnetic disk memory which comprises a disk pack seated on opposite sides of the housing and driven by a motor, and a magnetic head positioner head apparatus designed as a rotational positioner whose rotational axis is disposed parallel to the axis of the disk pack.
2. Description of the Prior Art
A distinction is generally made in magnetic disk memories between fixed disk memories and interchangeable disk memories. Technical development is continuing to proceed in the direction of higher and higher storage capacities, both with respect to a track density and the bit density as the characteristics for the storage capacity per disk surface, on the other hand, as well as in view of the mechanical structure in order to be able to accommodate as many disks as possible in a prescribed mounting space, on the other hand.
An example of this is the so-called 51/4" fixed disks memory whose magnetic disk have a outer diameter of 130 mm and an inner diameter of 40 mm according to the German industrial standard. Analogous to the dimensions of competing floppy disk drives, a mounting space having a mounting height of 82.5 mm and a base area of 146 mm.times.203 mm has crystallized for this type of storage as a uniform size which is available for the overall apparatus, including the housing and the appertaining electronics.
The desire to accommodate as many magnetic disks as possible in this prescribed mounting space is subordinate to the developmental goal of higher storage capacities and to the efforts to increase the recording density on the magnetic disk themselves. Within the scope of this structural desirability, embodiments of 51/4" fixed disk memories have been disclosed in which the drive motor for the disk pack has been miniaturized to such a degree and has been structurally designed such that it can be built into the hub of the disk pack, even given a prescribed inner diameter of 40 mm for the disk packs. An element which has a significant co-determining effect on the overall height of conventional fixed disk memories is therefore integrated into the hub of the magnetic disk pack and the overall height exploitable for the disk pack is thus expanded. Based on current conditions in the size of the combined magnetic heads and of the disk thickness, disk packs which contain up to eight magnetic disks stacked on top of one another have therefore become possible for 51/4" disk drives. The remaining overall height is required for the housing and the device electronics.
In order to guarantee adequate operating reliability given justifiable manufacturing costs, the desired, compact structure and high recording density on the magnetic disks necessitate special design measures. Given the dimensions of the disk pack, this can only be achieved with a housing which is designed stiff with respect to vibration.